1. Field of the Invention
This invention is concerned with a coating material containing modified chlorinated resins which are suitable for use as a vehicle in coating materials, printing inks or adhesives for plastics, especially polyolefin plastics.
2. Description of the Prior Art
U.S. Pat. No. 4,220,737 discloses an air drying composition. In this invention, at least one ingredient selected from the group consisting of chlorinated polydiolefin rubber and chlorinated polyolefin is used as a binder. Furthermore, these chlorinated polymers have a chlorine content of at least 55% by weight, preferably at least 60% by weight.
As in this U.S. patent disclosure, it is usual in the prior art that mixtures of chlorinated rubber and chlorinated polyethylene of high chlorine content, of more than 50% by weight with alkyd and/or other resins are used as vehicles for coating materials and others.
However, the coating film obtained by the use of such chlorinated polyolefin resin mixtures was poor in its weather resistance and accordingly entailed many disadvantages in practical use by the reason of high chlorine content, of more than 50% by weight.
On the other hand, it has been thought that low chlorine content resins have intrinsically more severe disadvantages as compared to those with high chlorine content.
The first reason: these low chlorine resins are insoluble or only slightly soluble in common organic solvents and a sufficiently concentration cannot be obtained.
The second reason: when the resins are soluble, the corresponding solutions are of poor stability; dechlorination occurs at higher temperatures, whilst viscosity increases or gelation occurs at lower temperatures.
Thus, the resins of this kind, including the above noted U.S. patent could not hitherto be put into practical use as vehicles for coating materials and the like.
Furthermore, a coating material, a printing ink or adhesive being suitable for polyolefin plastics, i.e. polyethylene plastics or polypropylene plastics are not new.